leandrof/linux
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

i2c: mpc: Poll for MCF

Browse Source 
During some transfers the bus can still be busy when an interrupt is
received. Commit 763778cd79 ("i2c: mpc: Restore reread of I2C status
register") attempted to address this by re-reading MPC_I2C_SR once but
that just made it less likely to happen without actually preventing it.
Instead of a single re-read, poll with a timeout so that the bus is given
enough time to settle but a genuine stuck SCL is still noticed.

Fixes: 1538d82f46 ("i2c: mpc: Interrupt driven transfer")
Signed-off-by: Chris Packham <chris.packham@alliedtelesis.co.nz>
Signed-off-by: Wolfram Sang <wsa@kernel.org>
This commit is contained in:
Chris Packham 2021-07-16 08:58:32 +12:00 committed by Wolfram Sang
parent a750bff5b9
commit 4a8ac5e45c
1 changed files with 2 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

4
drivers/i2c/busses/i2c-mpc.c
View File

@ -635,8 +635,8 @@ static irqreturn_t mpc_i2c_isr(int irq, void *dev_id)
status = readb(i2c->base + MPC_I2C_SR);
if (status & CSR_MIF) {
/* Read again to allow register to stabilise */
status = readb(i2c->base + MPC_I2C_SR);
/* Wait up to 100us for transfer to properly complete */
readb_poll_timeout(i2c->base + MPC_I2C_SR, status, !(status & CSR_MCF), 0, 100);
writeb(0, i2c->base + MPC_I2C_SR);
mpc_i2c_do_intr(i2c, status);
return IRQ_HANDLED;